Transmission device and reception device

ABSTRACT

A device that selects a transmission weight by which each of a plurality of signal points is to be multiplied; multiplies a signal corresponding to each of the plurality of signal points by the selected transmission weight; multiplexes the multiplied signals corresponding to each of the plurality of signal points on a same frequency and time resource; and modifies a selection rule corresponding to the transmission weight by which each of the plurality of signal points is to be multiplied.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Japanese Priority PatentApplication JP 2015-215632 filed Nov. 2, 2015, the entire contents ofwhich are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a transmission device and a receptiondevice.

BACKGROUND ART

Non-orthogonal multiple access (NOMA) has been attracting attention as aradio access technology (RAT) for a fifth generation (5G) mobilecommunication system following Long Term Evolution (LTE)/LTE-Advanced(LTE-A). In orthogonal frequency-division multiple access (OFDMA) andsingle-carrier frequency-division multiple access (SC-FDMA), which areadopted in LTE, radio resources (e.g., resource blocks) are allocated tousers without overlap. These schemes are called orthogonal multipleaccess. In contrast, in non-orthogonal multiple access, radio resourcesare allocated to users with overlap. In non-orthogonal multiple access,signals of users interfere with each other, but a signal for each useris taken out by a high-precision decoding process at the reception side.Non-orthogonal multiple access, in theory, achieves higher cellcommunication capability than orthogonal multiple access.

One of radio access technologies classified into non-orthogonal multipleaccess is superposition coding (SPC) multiplexing/multiple access. SPCis a scheme in which signals to which different powers are allocated aremultiplexed on at least partly overlapping radio resources in frequencyand time. At the reception side, interference cancellation and/oriterative detection is performed for reception/decoding of signalsmultiplexed on the same radio resource.

For example, PTLs 1 and 2 disclose, as SPC or a technology equivalent toSPC, techniques for setting an amplitude (or power) that allowsappropriate demodulation/decoding. Moreover, for example, PTL 3discloses a technique for enhancing successive interference cancellation(SIC) for reception of multiplexed signals.

CITATION LIST Patent Literature

-   PTL 1: JP 2003-78419A-   PTL 2: JP 2003-229835A-   PTL 3: JP 2013-247513A

SUMMARY Technical Problem

In signal processing technologies using SPC, there has been a demand foran improvement in decoding precision of multiplexed signals(interference signal and desired signal) of a plurality of power layers.

Hence, the present disclosure proposes a novel and improved transmissiondevice and reception device that can improve the precision of decodingfor obtaining a desired signal in performing multiplexing/multipleaccess using power allocation.

Solution to Problem

According to an embodiment of the present disclosure, there is provideda transmission device that selects a transmission weight by which eachof a plurality of signal points is to be multiplied; multiplies a signalcorresponding to each of the plurality of signal points by the selectedtransmission weight; multiplexes the multiplied signals corresponding toeach of the plurality of signal points on a same frequency and timeresource; and modifies a selection rule corresponding to thetransmission weight by which each of the plurality of signal points isto be multiplied.

According to an embodiment of the present disclosure, there is provideda device that acquires a report transmitted from a transmission devicethat selects a transmission weight by which each of a plurality ofsignal points is to be multiplied, multiplies a signal corresponding toeach signal point by the selected transmission weight, and multiplexesand transmits the multiplied signals corresponding to each of theplurality of signal points on a same frequency and time resource,wherein the report includes information indicating a switchable timingof the transmission weight; and

reports a switching request of the transmission weight to thetransmission device upon acquiring the report including informationindicating the switchable timing of the transmission weight

Advantageous Effects of Invention

According to an embodiment of the present disclosure, it is possible toprovide a novel and improved transmission device and reception devicethat can improve the precision of decoding for obtaining a desiredsignal in performing multiplexing/multiple access using powerallocation.

Note that the effects described above are not necessarily limitative.With or in the place of the above effects, there may be achieved any oneof the effects described in this specification or other effects that maybe grasped from this specification.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an explanatory diagram for explaining an example of a processin a transmission device that supports SPC.

FIG. 2 is an explanatory diagram for explaining an example of a processin a transmission device that supports SPC.

FIG. 3 is an explanatory diagram for explaining an example of a processin a reception device that performs interference cancellation.

FIG. 4 is an explanatory diagram for explaining the necessity ofinterference cancellation in a reception device in NOMA/SPC.

FIG. 5 is an explanatory diagram illustrating an example of an overallconfiguration of a communication network to which an embodiment of thepresent disclosure may be applied.

FIG. 6 illustrates an example of a difference between a logical entityand a physical network device.

FIG. 7 is an explanatory diagram illustrating a network configuration inmachine type communications (MTC).

FIG. 8 is an explanatory diagram illustrating a network configuration ofHetNet and SCE, which are targeted for the present embodiment.

FIG. 9 is an explanatory diagram illustrating an example of theschematic configuration of a system 1 according to an embodiment of thepresent disclosure.

FIG. 10 explains an example of the configuration of a base station 100according to an embodiment of the present disclosure.

FIG. 11 explains an example of the configuration of a terminal device200 according to an embodiment of the present disclosure.

FIG. 12 is a flowchart illustrating an operation example of the basestation 100 according to an embodiment of the present disclosure.

FIG. 13 is an explanatory diagram for explaining a method for selectinga transmission weight by the base station 100 according to an embodimentof the present disclosure.

FIG. 14 is a flowchart illustrating an operation example of the basestation 100 (transmitter) and the terminal device 200 (receiver)according to an embodiment of the present disclosure.

FIG. 15 is an explanatory diagram illustrating an example of associatinga codebook index with a power layer.

FIG. 16 is an explanatory diagram illustrating an example of receptioncharacteristics for combinations of codebook indices.

FIG. 17 is a block diagram illustrating a first example of a schematicconfiguration of an eNB.

FIG. 18 is a block diagram illustrating a second example of theschematic configuration of the eNB.

FIG. 19 is a block diagram illustrating an example of a schematicconfiguration of a smartphone.

FIG. 20 is a block diagram illustrating an example of a schematicconfiguration of a car navigation device.

DESCRIPTION OF EMBODIMENTS

Hereinafter, (a) preferred embodiment(s) of the present disclosure willbe described in detail with reference to the appended drawings. In thisspecification and the appended drawings, structural elements that havesubstantially the same function and structure are denoted with the samereference numerals, and repeated explanation of these structuralelements is omitted.

Description will be given in the following order.

1. Embodiment of present disclosure

1.1. Overview

1.2. Configuration example

1.3. Operation example

2. Application examples regarding base stations

3. Application examples regarding terminal devices

4. Conclusion

1. Embodiment of Present Disclosure 1.1. Overview

First, an overview of an embodiment of the present disclosure will bedescribed. Firstly described with reference to the drawings areprocesses and signals of SPC.

(1) Process in Each Device

(a) Process in Transmission Device

FIGS. 1 and 2 are explanatory diagrams for explaining an example of aprocess in a transmission device that supports SPC. According to FIG. 1,for example, bit streams (e.g., transport blocks) of a user A, a user B,and a user C are processed. For each of these bit streams, someprocesses (e.g., cyclic redundancy check (CRC) encoding, forward errorcorrection (FEC) encoding, rate matching, and scrambling/interleaving,as illustrated in FIG. 2) are performed and then modulation isperformed. Further, layer mapping, power allocation, precoding, SPCmultiplexing, resource element mapping, inverse discrete Fouriertransform (IDFT)/inverse fast Fourier transform (IFFT), cyclic prefix(CP) insertion, digital-to-analog and radio frequency (RF) conversion,and the like are performed.

In particular, in power allocation, power is allocated to signals of theuser A, the user B, and the user C, and in SPC multiplexing, the signalsof the user A, the user B, and the user C are multiplexed.

(b) Process in Reception Device

FIG. 3 is an explanatory diagram for explaining an example of a processin a reception device that performs interference cancellation. Accordingto FIG. 3, for example, RF and analog-to-digital conversion, CP removal,discrete Fourier transform (DFT)/fast Fourier transform (FFT), jointinterference cancellation, equalization, decoding, and the like areperformed. This provides bit streams (e.g., transport blocks) of theuser A, the user B, and the user C.

(2) Transmission Signals and Reception Signals

(a) Downlink

Next, downlink transmission signals and reception signals when SPC isadopted will be described. Assumed here is a multi-cell system ofheterogeneous network (HetNet), small cell enhancement (SCE), or thelike.

An index of a cell to be in connection with a target user u is denotedby i, and the number of transmission antennas of a base stationcorresponding to the cell is denoted by N_(TX,i). Each of thetransmission antennas may also be called a transmission antenna port. Atransmission signal from the cell i to the user u can be expressed in avector form as below.

$\begin{matrix}{s_{i,u} = {\begin{bmatrix}s_{i,u,0} \\\vdots \\s_{i,u,{N_{{TX},i} - 1}}\end{bmatrix} = {W_{i,u}P_{i,u}x_{i,u}}}} & \left\lbrack {{Math}.\mspace{14mu} 1} \right\rbrack \\{W_{i,u} = \begin{bmatrix}w_{i,u,0,0} & \cdots & w_{i,u,0,{N_{{SS},u} - 1}} \\\vdots & \ddots & \vdots \\w_{i,u,{N_{{TX},i} - 1},0} & \cdots & w_{i,u,{N_{{TX},i} - 1},{N_{{SS},u} - 1}}\end{bmatrix}} & \left\lbrack {{Math}.\mspace{14mu} 2} \right\rbrack \\{P_{i,u} = \begin{bmatrix}P_{i,u,0,0} & \cdots & P_{i,u,0,{N_{{SS},u} - 1}} \\\vdots & \ddots & \vdots \\P_{i,u,{N_{{SS},u} - 1},0} & \cdots & P_{i,u,{N_{{SS},u} - 1},{N_{{SS},u} - 1}}\end{bmatrix}} & \left\lbrack {{Math}.\mspace{14mu} 3} \right\rbrack \\{x_{i,u} = \begin{bmatrix}x_{i,u,0} \\\vdots \\x_{i,u,{N_{{SS},u} - 1}}\end{bmatrix}} & \left\lbrack {{Math}.\mspace{14mu} 4} \right\rbrack\end{matrix}$

In the above expressions, N_(SS,u) denotes the number of spatialtransmission streams for the user u. Basically, N_(SS,u) is a positiveinteger equal to or less than N_(Tx,i). A vector x_(i,u) is a spatialstream signal to the user u. Elements of this vector basicallycorrespond to digital modulation symbols of phase shift keying (PSK),quadrature amplitude modulation (QAM), or the like. A matrix W_(i,u) isa precoding matrix for the user u. An element in this matrix isbasically a complex number, but may be a real number.

A matrix P_(1,u) is a power allocation coefficient matrix for the user uin the cell i. In this matrix, each element is preferably a positivereal number. Note that this matrix may be a diagonal matrix (i.e., amatrix whose components excluding diagonal components are zero) asbelow.

$\begin{matrix}{P_{i,u} = \begin{bmatrix}P_{i,u,0,0} & 0 & \cdots & 0 \\0 & P_{i,u,1,1} & \ddots & \vdots \\\vdots & \ddots & \ddots & 0 \\0 & \cdots & \cdots & P_{i,u,{N_{{SS},u} - 1},{N_{{SS},u} - 1}}\end{bmatrix}} & \left\lbrack {{Math}.\mspace{14mu} 5} \right\rbrack\end{matrix}$

If adaptive power allocation for a spatial stream is not performed, ascalar value P_(i,u) may be used instead of the matrix P_(i,u).

As well as the user u, another user v is present in the cell i, and asignal s_(i,v) of the other user v is also transmitted on the same radioresource. These signals are multiplexed by SPC. A signal s_(i) from thecell i after multiplexing is expressed as below.

$\begin{matrix}{s_{i} = {\sum\limits_{u^{\prime} \in U_{i}}s_{i,u^{\prime}}}} & \left\lbrack {{Math}.\mspace{14mu} 6} \right\rbrack\end{matrix}$

In the above expression, U_(i) denotes a set of users for whichmultiplexing is performed in the cell i. Also in a cell j (a cell thatserves as an interference source for the user u) other than a servingcell of the user u, a transmission signal s_(j) is generated similarly.Such a signal is received as interference at the user side. A receptionsignal r_(u) of the user u can be expressed as below.

$\begin{matrix}{r_{u} = {\begin{bmatrix}r_{u,0} \\\vdots \\r_{u,{N_{{RX},u} - 1}}\end{bmatrix} = {{\sum\limits_{i^{\prime}}{H_{u,i^{\prime}}s_{i^{\prime}}}} + n_{u}}}} & \left\lbrack {{Math}.\mspace{14mu} 7} \right\rbrack \\{H_{u,i} = \begin{bmatrix}h_{u,i,0,0} & \cdots & h_{u,i,0,{N_{{TX},i} - 1}} \\\vdots & \ddots & \vdots \\h_{u,i,{N_{{RX},u} - 1},0} & \cdots & h_{u,i,{N_{{RX},u} - 1},{N_{{TX},i} - 1}}\end{bmatrix}} & \left\lbrack {{Math}.\mspace{14mu} 8} \right\rbrack \\{n_{u} = \begin{bmatrix}n_{u,0} \\\vdots \\n_{u,{N_{{RX},u} - 1}}\end{bmatrix}} & \left\lbrack {{Math}.\mspace{14mu} 9} \right\rbrack\end{matrix}$

In the above expressions, a matrix H_(u,i) is a channel response matrixfor the cell i and the user u. Each element of the matrix H_(u,i) isbasically a complex number. A vector n_(u) is noise included in thereception signal r_(u) of the user u. For example, the noise includesthermal noise and interference from another system. The average power ofthe noise is expressed as below.

σ_(n,u)  [Math.10]

The reception signal r_(u) can also be expressed by a desired signal andanother signal as below.

$\begin{matrix}{r_{u} = {{H_{u,i}s_{i,u}} + {H_{u,i}{\sum\limits_{{v \in U_{i}},{v \neq u}}s_{i,v}}} + {\sum\limits_{j \neq i}{H_{u,j}{\sum\limits_{v \in U_{j}}s_{j,v}}}} + n_{u}}} & \left\lbrack {{Math}.\mspace{14mu} 11} \right\rbrack\end{matrix}$

In the above expression, the first term of the right side denotes adesired signal of the user u, the second term, interference in theserving cell i of the user u (called intra-cell interference, multi-userinterference, multi-access interference, or the like), and the thirdterm, interference from a cell other than the cell i (called inter-cellinterference).

When orthogonal multiple access (e.g., OFDMA or SC-FDMA) or the like isadopted, the reception signal can be expressed as below.

$\begin{matrix}{r_{u} = {{H_{u,i}s_{i,u}} + {\sum\limits_{j \neq i}{H_{u,j}s_{j,v}}} + n_{u}}} & \left\lbrack {{Math}.\mspace{14mu} 12} \right\rbrack\end{matrix}$

In orthogonal multiple access, no intra-cell interference occurs, andmoreover, in the other cell j, a signal of the other user v is notmultiplexed on the same radio resource.

(b) Uplink

Next, uplink transmission signals and reception signals when SPC isadopted will be described. Assumed here is a multi-cell system ofHetNet, SCE, or the like. Note that the signs used for downlink will befurther used as signs denoting signals and the like.

A transmission signal that the user u transmits in the cell i can beexpressed in a vector form as below.

$\begin{matrix}{s_{i,u} = {\begin{bmatrix}s_{i,u,0} \\\vdots \\s_{i,u,{N_{{TX},u} - 1}}\end{bmatrix} = {W_{i,u}P_{i,u}x_{i,u}}}} & \left\lbrack {{Math}.\mspace{14mu} 13} \right\rbrack \\{W_{i,u} = \begin{bmatrix}w_{i,u,0,0} & \cdots & w_{i,u,0,{N_{{SS},u} - 1}} \\\vdots & \ddots & \vdots \\w_{i,u,{N_{{TX},u} - 1},0} & \cdots & w_{i,u,{N_{{TX},u} - 1},{N_{{SS},u} - 1}}\end{bmatrix}} & \left\lbrack {{Math}.\mspace{14mu} 14} \right\rbrack \\{P_{i,u} = \begin{bmatrix}P_{i,u,0,0} & \cdots & P_{i,u,0,{N_{{SS},u} - 1}} \\\vdots & \ddots & \vdots \\P_{i,u,{N_{{SS},u} - 1},0} & \cdots & P_{i,u,{N_{{SS},u} - 1},{N_{{SS},u} - 1}}\end{bmatrix}} & \left\lbrack {{Math}.\mspace{14mu} 15} \right\rbrack \\{x_{i,u} = \begin{bmatrix}x_{i,u,0} \\\vdots \\x_{i,u,{N_{{SS},u} - 1}}\end{bmatrix}} & \left\lbrack {{Math}.\mspace{14mu} 16} \right\rbrack\end{matrix}$

In the above expressions, the number of transmission antennas is thenumber of transmission antennas of the user, N_(TX,u). As in downlink, amatrix P_(i,u), which is a power allocation coefficient matrix for theuser u in the cell i, may be a diagonal matrix.

In uplink, there is no case where a signal of a user and a signal ofanother user are multiplexed in the user; thus, a reception signal of abase station of the cell i can be expressed as below.

$\begin{matrix}{r_{i} = {\begin{bmatrix}r_{i,0} \\\vdots \\r_{i,{N_{{RX},i} - 1}}\end{bmatrix} = {{\sum\limits_{i^{\prime}}{\sum\limits_{u^{\prime} \in U_{i}^{\prime}}H_{i^{\prime},u^{\prime}}s_{i^{\prime},u^{\prime}}}} + n_{i}}}} & \left\lbrack {{Math}.\mspace{14mu} 17} \right\rbrack \\{H_{i,u} = \begin{bmatrix}h_{i,u,0,0} & \cdots & h_{i,u,0,{N_{{TX},u} - 1}} \\\vdots & \ddots & \vdots \\h_{i,u,{N_{{RX},i} - 1},0} & \cdots & h_{i,u,{N_{{RX},i} - 1},{N_{{TX},u} - 1}}\end{bmatrix}} & \left\lbrack {{Math}.\mspace{14mu} 18} \right\rbrack \\{n_{i} = \begin{bmatrix}n_{i,0} \\\vdots \\n_{i,{N_{{RX},i} - 1}}\end{bmatrix}} & \left\lbrack {{Math}.\mspace{14mu} 19} \right\rbrack\end{matrix}$

It should be noted that in uplink, unlike in downlink, a base stationneeds to obtain all signals from a plurality of users in a cell bydecoding. Note also that a channel response matrix differs depending ona user.

When a focus is put on a signal transmitted by the user u, among uplinksignals in the cell i, a reception signal can be expressed as below.

$\begin{matrix}{r_{i,u} = {\begin{bmatrix}r_{i,u,0} \\\vdots \\r_{i,u,{N_{{RX},i} - 1}}\end{bmatrix} = {{H_{i,u}s_{i,u}} + {\sum\limits_{{v \in U_{i}},{v \neq u}}{H_{i,v}s_{i,v}}} + {\sum\limits_{j \neq i}{\sum\limits_{v \in U_{j}}{H_{i,v}s_{j,v}}}} + n_{i}}}} & \left\lbrack {{Math}.\mspace{14mu} 20} \right\rbrack\end{matrix}$

In the above expression, the first term of the right side denotes adesired signal of the user u, the second term, interference in theserving cell i of the user u (called intra-cell interference, multi-userinterference, multi-access interference, or the like), and the thirdterm, interference from a cell other than the cell i (called inter-cellinterference).

When orthogonal multiple access (e.g., OFDMA or SC-FDMA) or the like isadopted, the reception signal can be expressed as below.

$\begin{matrix}{r_{i,u} = {{H_{i,u}s_{i,u}} + {\sum\limits_{j \neq i}{H_{i,v}s_{j,v}}} + n_{i}}} & \left\lbrack {{Math}.\mspace{14mu} 21} \right\rbrack\end{matrix}$

In orthogonal multiple access, no intra-cell interference occurs, andmoreover, in the other cell j, a signal of the other user v is notmultiplexed on the same radio resource.

(3) Background of Embodiment

Now, a background to an embodiment of the present disclosure will bedescribed.

In SPC, in receiving and decoding signals multiplexed in a power domainwith high precision, it is possible to use SIC in a reception-sidedevice. In using SIC in the reception-side device, how to improveinterference cancellation performance is important. Moreover, even ifinterference cancellation performance is insufficient, how toeffectively utilize the performance of FEC decoding following theinterference cancellation is of consequence. To improve suchperformance, in a transmission-side device, only using SPC in relatedart is insufficient and it is necessary to perform a process forefficiently melding interference cancellation and FEC decoding.

Furthermore, to achieve efficient interference cancellation and FECdecoding, it is preferable to consider also backward compatibility. Inrelated art, PTL 2 discloses, as interference randomization for aninterference cancellation effect, a technology of applying interleavingfor each cell. However, the technology disclosed in PTL 2, in whichtechnology all devices need to have SIC and interference cancellationfunctions, is disadvantageous in backward compatibility. In addition, aneffect of interference cancellation between SPC-multiplexed signalscannot be expected from interleaving for each cell.

Moreover, in recent communication systems, importance is placed onmulti-input multi-output (MIMO), which uses a plurality of antennas in atransmission device and a reception device. In the case of furtherapplying SPC and an interleaving technology to a communication systemadopting this MIMO, there is a need for multiplexing and interleaverselection including a spatial domain in addition to a power domain.Patent Literatures described above do not disclose this point, thusbeing insufficient in improving characteristics.

Hereinafter, basic power allocation in NOMA/SPC and an issue of areception device will be described. FIG. 4 is an explanatory diagram forexplaining the necessity of interference cancellation in a receptiondevice in NOMA/SPC.

In NOMA/SPC, a plurality of signals are multiplexed by being given apower level difference on at least partly the same frequency resourceand time resource. FIG. 4 illustrates a case where signals to twodevices (Far UE and Near UE) in downlink are multiplexed with differentpowers.

In general, allocation of power levels is preferably set according to arelative relationship in path loss (alternatively, path gain or assumedreception quality (SINR)) between a transmission device and a receptiondevice, taking into consideration the upper limit of the totaltransmission power of the transmission device. In the case of path loss,a high power is allocated to a signal to a device with large path loss(Far UE in FIG. 4), such as a farther device or a device that is outsidea main lobe of antenna directivity, and a low power is allocated to asignal to a device with small path loss (Near UE in FIG. 4), such as acloser device or a device that is inside a main lobe of antennadirectivity.

When signals are transmitted from a base station with a power leveldifference given in this way, signal-to-interference ratio (SIR) inNOMA/SPC is predicted to be 1 or more (0 dB or more) for Far UE, and 1or less (0 dB or less) for Near UE. In other words, particularly in NearUE, it is necessary to perform interference cancellation, for example,on signals to Far UE serving as interference in order to obtain signalsto Near UE itself by decoding.

In the case where SPC is performed, complex signal points (symbols) tobe transmitted are multiplied by a transmission weight selected for eachsignal. The signals are multiplied by the transmission weights. Hence,how to decide a transmission weight in terms of interferencecancellation characteristics seems to be an issue. In LTE, for example,in transmission mode (TM) 3, TM4, TM5, TM6, TM8 and TM9, a weight to beapplied is selected from a transmission weight table of Table 1 or Table2 to be used for calculation of a transmission weight. In SPC, however,interference occurs between multiplexed signals; thus, some combinationsof selected transmission weights may lead to poor bit error ratecharacteristics.

TABLE 1 (Transmission weight table used in TM3 when the number ofantenna ports is two) Codebook Number of layers υ index 1 2 0$\frac{1}{\sqrt{2}}\begin{bmatrix}1 \\1\end{bmatrix}$ $\frac{1}{\sqrt{2}}\begin{bmatrix}1 & 0 \\0 & 1\end{bmatrix}$ 1 $\frac{1}{\sqrt{2}}\begin{bmatrix}1 \\{- 1}\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 & 1 \\1 & {- 1}\end{bmatrix}$ 2 $\frac{1}{\sqrt{2}}\begin{bmatrix}1 \\j\end{bmatrix}$ $\frac{1}{2}\begin{bmatrix}1 & 1 \\j & {- j}\end{bmatrix}$ 3 $\frac{1}{\sqrt{2}}\begin{bmatrix}1 \\{- j}\end{bmatrix}$ —

TABLE 2 (Transmission weight table used when the number of antenna portsis 4) Number of layers υ Codebook Index u_(n) 1 2 3 4 0 u₀ = [1 −1 −1−1]^(T) W₀ ^({1}) W₀ ^({14})/{square root over (2)} W₀ ^({124})/{squareroot over (3)} W₀ ^({1234})/2 1 u₁ = [1 −j 1 j]^(T) W₁ ^({1}) W₁^({12})/{square root over (2)} W₁ ^({123})/{square root over (3)} W₁^({1234})/2 2 u₂ = [1 1 −1 1]^(T) W₂ ^({1}) W₂ ^({12})/{square root over(2)} W₂ ^({123})/{square root over (3)} W₂ ^({3214})/2 3 u₃ = [1 j 1−j]^(T) W₃ ^({1}) W₃ ^({12})/{square root over (2)} W₃ ^({123})/{squareroot over (3)} W₃ ^({3214})/2 4 u₄ = [1 (−1 − j)/{square root over (2)}−j (1 − j)/{square root over (2)}]^(T) W₄ ^({1}) W₄ ^({14})/{square rootover (2)} W₄ ^({124})/{square root over (3)} W₄ ^({1234})/2 5 u₅ = [1 (1− j)/{square root over (2)} j (−1 − j)/{square root over (2)}]^(T) W₅^({1}) W₅ ^({14})/{square root over (2)} W₅ ^({124})/{square root over(3)} W₅ ^({1234})/2 6 u₆ = [1 (1 + j)/{square root over (2)} −j (−1 +j)/{square root over (2)}]^(T) W₆ ^({1}) W₆ ^({13})/{square root over(2)} W₆ ^({134})/{square root over (3)} W₆ ^({1324})/2 7 u₇ = [1 (−1 +j)/{square root over (2)} j (1 + j)/{square root over (2)}]^(T) W₇^({1}) W₇ ^({13})/{square root over (2)} W₇ ^({134})/{square root over(3)} W₇ ^({1324})/2 8 u₈ = [1 −1 1 1]^(T) W₈ ^({1}) W₈ ^({12})/{squareroot over (2)} W₈ ^({124})/{square root over (3)} W₈ ^({1234})/2 9 u₉ =[1 −j −1 −j]^(T) W₉ ^({1}) W₉ ^({14})/{square root over (2)} W₉^({134})/{square root over (3)} W₉ ^({1234})/2 10 u₁₀ = [1 1 1 −1]^(T)W₁₀ ^({1}) W₁₀ ^({13})/{square root over (2)} W₁₀ ^({123})/{square rootover (3)} W₁₀ ^({1324})/2 11 u₁₁ = [1 j −1 j]^(T) W₁₁ ^({1}) W₁₁^({13})/{square root over (2)} W₁₁ ^({134})/{square root over (3)} W₁₁^({1324})/2 12 u₁₂ = [1 −1 −1 1]^(T) W₁₂ ^({1}) W₁₂ ^({12})/{square rootover (2)} W₁₂ ^({123})/{square root over (3)} W₁₂ ^({1234})/2 13 u₁₃ =[1 −1 1 −1]^(T) W₁₃ ^({1}) W₁₃ ^({13})/{square root over (2)} W₁₃^({123})/{square root over (3)} W₁₃ ^({1324})/2 14 u₁₄ = [1 1 −1 −1]^(T)W₁₄ ^({1}) W₁₄ ^({13})/{square root over (2)} W₁₄ ^({123})/{square rootover (3)} W₁₄ ^({3214})/2 15 u₁₅ = [1 1 1 1]^(T) W₁₅ ^({1}) W₁₅^({12})/{square root over (2)} W₁₅ ^({123})/{square root over (3)} W₁₅^({1234})/2

FIG. 5 is an explanatory diagram illustrating an example of an overallconfiguration of a communication network to which an embodiment of thepresent disclosure may be applied. “Device layer” in FIG. 5 includes, aswell as a user terminal device, a communication device having a radiocommunication function, such as a base station device (e.g., NodeB (NB),eNB, or access point (AP)). Although not illustrated, the user terminaldevice and the base station device may be further classified intodifferent layers. In that case, the base station device is preferablycloser to a core network.

In the configuration example of the communication network illustrated inFIG. 5, the user terminal device belonging to the device layer uses aservice provided by an application server device via a network. Alogical session can be considered as communication between the userterminal device and the application server device.

On the other hand, from the view point of connection between networklayers, a network configuration can be considered in addition to thelogical session. For example, in the case where a communication devicein the device layer constitutes a cellular system, one or more basestation devices are connected to a control/user data network of thecellular system, which is called a core network. Further, they areconnected to a public Internet Protocol (IP) network via a gatewaydevice in the core network. Meanwhile, the application server device canbe considered as one element that constitutes a service platformtogether with a plurality of other servers, as in a cloud system. Insuch a case, a communication device corresponding to a gateway may beinstalled at the service platform side to serve a function inestablishing connection with the public IP network.

The core network, the IP network, and the service platform may furtherinclude, as physical communication devices, a virtualization device thatvirtualizes a network (e.g., a router, a switch, and a router/switch), anetwork virtualization control device, and a cable. FIG. 6 illustratesan example of a difference between a logical entity and a physicalnetwork device. For example, there is an interface called X2 interfacebetween base station devices. It should be noted that this is a logicalinterface, and the base station devices are actually not necessarily indirect physical connection. They may actually be connected physicallyvia a plurality of entities.

A radio access technology (RAT) targeted for an embodiment of thepresent disclosure is a technology for radio connection particularlybetween communication devices belonging to the device layer in theconfiguration example of the network illustrated in FIG. 5.

FIG. 7 is an explanatory diagram illustrating a network configuration inmachine type communications (MTC), which is another example of acommunication network configuration. The RAT in an embodiment of thepresent disclosure corresponds to an access scheme used in a radioaccess network (RAN) in the drawing. A user equipment (UE) correspondsto the terminal device, and it is assumed that an MTC application isoperating on the UE. The base station device is not explicit in FIG. 7,but is assumed to be present in the RAN in connection with the UE.

A “home public land mobile network (HPLMN)” and a “visited public landmobile network (VPLMN)” in FIG. 7 indicate a configuration for roamingbetween different common carriers. The HPLMN is a network on the commoncarrier side to which the target communication device (e.g., UE)originally belongs, and the VPLMN corresponds to a network that is aroaming destination of the communication device. Although omitted fromFIG. 7, a public IP network may serve as a relay between the HPLMN andthe VPLMN. During roaming, as illustrated in FIG. 7, particularly dataof a control plane is relayed from the VPLMN to an entity in the HPLMN.This is because control information of the target UE needs to be managedon the home common carrier side. Meanwhile, data of a user plane isrelayed from a gateway on the VPLMN side to a gateway on the HPLMN sideand then relayed and transferred to an application server (the data maygo through an entity of a public IP network or a service platform). Innormal operation without roaming, there is no HPLMN/VPLMN boundary.

In the case where an application server provides a service, it ispossible to further install a service capability server (SCS) toappropriately select a service that can be provided. For example, inproviding a service, if it is necessary to carry out monitoring andsensing for a target UE beforehand, the SCS may request a triggertherefor from the UE so that provision of the service can be smoothlystarted. The SCS is not necessary for all application servers, and forexample, as illustrated in FIG. 7, it is possible to adopt a hybridconfiguration in which an application server accompanied by a SCS and anapplication server not accompanied by a SCS are used in accordance witha service to be provided.

FIG. 8 is an explanatory diagram illustrating a network configuration ofHetNet and SCE, which are targeted for the present embodiment. Linesshown by the broken lines in FIG. 8 indicate logical connection, and donot necessarily indicate direct physical connection.

A communication area includes “cells”, indicated by ovals in FIG. 8, inwhich a plurality of base stations each provide a service. One basestation may provide a plurality of cells. FIG. 8 illustrates a macrocell base station 40 and a small cell base station 50. The macro cellbase station 40 covers a macro cell area 41, and the small cell basestation 50 covers a small cell area 51 that is narrower than the macrocell area 41. In the following description, the macro cell base station40 and the small cell base station 50 are collectively described as“base stations” in some cases.

A base station can communicate with other base stations via a backhaul,and mainly exchanges control information. The backhaul may be eitherwired or wireless. This backhaul may adopt information exchange using aprotocol of X2 interface or S1 interface, for example.

The base station also has a backhaul to a core network 33 of a system.The base station may be connected to a control entity 34 to be broughtinto connection with the core network 33. In other words, the controlentity 34 may be regarded as an element of the core network 33. Further,the base station may be connected to the core network 33 via an externalnetwork 30 and a gateway device 31, as well as via the control entity34. Examples of such a case are a femtocell base station device and aHome eNB (HeNB) device, which can be installed in a room or in ahousehold. The femtocell base station device or HeNB device may beconnected to the external network 30 via a HeNB gateway device 32, forexample.

The small cell area 51 is basically arranged to overlap with the macrocell area 41. Alternatively, the small cell area 51 may be partially thesame as the macro cell area 41 or arranged completely outside the macrocell area 41.

A macro cell and a small cell may have a characteristic in radioresources to be used. For example, the macro cell and the small cell mayuse the same frequency resource F1 (or time resource T1). The macro celland the small cell using the same frequency resource F1 (or timeresource T1) can improve radio resource use efficiency of the entiresystem.

It is also possible for the macro cell to use the frequency resource F1(or time resource T1) and the small cell to use a frequency resource F2(or time resource T2). The macro cell and the small cell using differentfrequency resources (or time resources) can allow interference betweenthe macro cell and the small cell to be avoided. Further alternatively,both kinds of cells may use F1/2 (T1/2). This is an idea equivalent tocarrier aggregation (CA) when applied particularly to frequencyresources.

1.2. Configuration Example

Now, a schematic configuration of a system 1 according to an embodimentof the present disclosure will be described with reference to FIG. 9.FIG. 9 is an explanatory diagram illustrating an example of theschematic configuration of the system 1 according to an embodiment ofthe present disclosure. According to FIG. 9, the system 1 includes abase station 100 and a terminal device 200. Here, the terminal device200 is also called a user. The user may also be called a user equipment(UE). Here, the UE may be a UE defined in LTE or LTE-A, or may generallyrefer to communication equipment.

(1) Base Station 100

The base station 100 is a base station of a cellular system (or mobilecommunication system). The base station 100 performs radio communicationwith a terminal device (e.g., the terminal device 200) located in a cell10 of the base station 100. For example, the base station 100 transmitsa downlink signal to the terminal device, and receives an uplink signalfrom the terminal device.

(2) Terminal Device 200

The terminal device 200 can perform communication in a cellular system(or mobile communication system). The terminal device 200 performs radiocommunication with a base station (e.g., the base station 100) of thecellular system. For example, the terminal device 200 receives adownlink signal from the base station, and transmits an uplink signal tothe base station.

(3) Multiplexing/Multiple Access

In particular, in an embodiment of the present disclosure, the basestation 100 performs radio communication with a plurality of terminaldevices by non-orthogonal multiple access. Specifically, the basestation 100 performs radio communication with the plurality of terminaldevices by multiplexing/multiple access using power allocation. Forexample, the base station 100 performs radio communication with theplurality of terminal devices by multiplexing/multiple access using SPC.

For example, the base station 100 performs radio communication with theplurality of terminal devices by multiplexing/multiple access using SPCin downlink. Specifically, for example, the base station 100 multiplexessignals to the plurality of terminal devices using SPC. In this case,for example, the terminal device 200 removes one or more other signals,as interference, from a multiplexed signal including a desired signal(i.e., a signal to the terminal device 200), and decodes the resultingsignal into the desired signal.

Note that the base station 100 may perform radio communication with theplurality of terminal devices by multiplexing/multiple access using SPCin uplink, instead of or together with downlink. In this case, the basestation 100 may decode a multiplexed signal including signalstransmitted from the plurality of terminal devices into the signals.

Now, configurations of the base station 100 and the terminal device 200according to an embodiment of the present disclosure will be describedwith reference to FIGS. 10 and 11.

First, an example of the configuration of the base station 100 accordingto an embodiment of the present disclosure will be described withreference to FIG. 10. FIG. 10 is a block diagram illustrating theexample of the configuration of the base station 100 according to anembodiment of the present disclosure. According to FIG. 10, the basestation 100 includes an antenna unit 110, a radio communication unit120, a network communication unit 130, a storage unit 140, and aprocessing unit 150.

(1) Antenna Unit 110

The antenna unit 110 radiates signals output by the radio communicationunit 120 out into space as radio waves. In addition, the antenna unit110 converts radio waves in the space into signals, and outputs thesignals to the radio communication unit 120.

(2) Radio Communication Unit 120

The radio communication unit 120 transmits and receives signals. Forexample, the radio communication unit 120 transmits a downlink signal toa terminal device, and receives an uplink signal from a terminal device.

(3) Network Communication Unit 130

The network communication unit 130 transmits and receives information.For example, the network communication unit 130 transmits information toother nodes, and receives information from other nodes. For example, theother nodes include another base station and a core network node.

(4) Storage Unit 140

The storage unit 140 temporarily or permanently stores a program andvarious data for operation of the base station 100.

(5) Processing Unit 150

The processing unit 150 provides various functions of the base station100. The processing unit 150 includes a transmission processing unit 151and a reporting unit 153. Note that the processing unit 150 may furtherinclude a structural element other than these structural elements. Thatis, the processing unit 150 may perform operation other than theoperation of these structural elements.

The operation of the transmission processing unit 151 and the reportingunit 153 will be described in detail later.

Next, an example of the configuration of the terminal device 200according to an embodiment of the present disclosure will be describedwith reference to FIG. 11. FIG. 11 is a block diagram illustrating theexample of the configuration of the terminal device 200 according to anembodiment of the present disclosure. According to FIG. 11, the terminaldevice 200 includes an antenna unit 210, a radio communication unit 220,a storage unit 230, and a processing unit 240.

(1) Antenna Unit 210

The antenna unit 210 radiates signals output by the radio communicationunit 220 out into space as radio waves. In addition, the antenna unit210 converts radio waves in the space into signals, and outputs thesignals to the radio communication unit 220.

(2) Radio Communication Unit 220

The radio communication unit 220 transmits and receives signals. Forexample, the radio communication unit 220 receives a downlink signalfrom a base station, and transmits an uplink signal to a base station.

(3) Storage Unit 230

The storage unit 230 temporarily or permanently stores a program andvarious data for operation of the terminal device 200.

(4) Processing Unit 240

The processing unit 240 provides various functions of the terminaldevice 200. The processing unit 240 includes an acquisition unit 241, areception processing unit 243, and a reporting unit 245. Note that theprocessing unit 240 may further include a structural element other thanthese structural elements. That is, the processing unit 240 may performoperation other than the operation of these structural elements.

The operation of the acquisition unit 241, the reception processing unit243, and the reporting unit 245 will be described in detail later.

1.3. Operation Example

Now, an operation example of the base station 100 and the terminaldevice 200 according to an embodiment of the present disclosure will bedescribed.

(1) Method for Selecting Transmission Weights by which Signals to beSPCMultiplexed are to be Multiplied

First, description is given on how the base station 100 selectstransmission weights by which signals to be SPC-multiplexed (i.e., to bemultiplexed by being given a power level difference on at least partlythe same frequency resource and time resource) are to be multiplied.

FIG. 12 is a flowchart illustrating an operation example of the basestation 100 according to an embodiment of the present disclosure. Theflowchart in FIG. 12 illustrates a method for selecting transmissionweights by which signals to be SPC-multiplexed are to be multiplied.Hereinafter, the operation example of the base station 100 according toan embodiment of the present disclosure will be described using FIG. 12.In the following description, the number of signals to be multiplexed isassumed to be two. The flowchart in FIG. 12 is the operation example ofthe base station 100 when one of the two signals to be multiplexed istargeted for switching of a transmission weight selection rule.

The base station 100 determines whether a target signal is a signal tobe multiplexed with another signal on at least partly the same frequencyor time resource (step S101). The process of step S101 is executed bythe transmission processing unit 151, for example.

When it is determined in step S101 that the target signal is a signal tobe multiplexed with another signal on at least partly the same frequencyor time resource (step S101, Yes), the base station 100 then determineswhether a power level lower than that of the other signal is allocatedto the target signal (step S102). The process of step S102 is executedby the transmission processing unit 151, for example.

When it is determined in step S102 that a power level lower than that ofthe other signal is allocated to the target signal (step S102, Yes), thebase station 100 then determines whether a transmission weight by whichthe target signal is to be multiplied is a quasi-statically decidedweight (step S103). The process of step S103 is executed by thetransmission processing unit 151, for example. Whether a transmissionweight is a quasi-statically decided weight means whether thetransmission weight is a weight decided as shown in Table 1, forexample.

When it is determined in step S103 that a transmission weight by whichthe target signal is to be multiplied is a quasi-statically decidedweight (step S103, Yes), the base station 100 then switches thetransmission weight selection rule and selects a transmission weight bywhich the signal is to be multiplied (step S104). The process of stepS104 is executed by the transmission processing unit 151, for example.

When the results of determination in steps S101 to S103 are negative,the base station 100 decides to conform to a transmission weightselection rule in related art (step S105).

Finally, the base station 100 multiplies a transmission signal by atransmission weight selected in step S104 or a transmission weightdecided according to the transmission weight selection rule in relatedart decided in step S105 (step S106). The process of step S106 isexecuted by the transmission processing unit 151, for example.

Now, description is given on a method for selecting a transmissionweight in step S104 when it has been decided to switch the transmissionweight selection rule. Switching of a selection rule may be, forexample, switching of a rule in accordance with power layer informationor a state (e.g., transmission weight category) of the other signal tobe multiplexed.

FIG. 13 is an explanatory diagram for explaining a method for selectinga transmission weight by the base station 100 according to an embodimentof the present disclosure. FIG. 13 illustrates an example of switching aconversion rule in accordance with a state of a signal constellation ofsignals to be multiplexed. Illustrated in FIG. 13 is a case of selectingtransmission weights for two signal points 0 and 1. The signal point 0is a signal point to which a high power level is to be allocated, andthe signal point 1 is a signal point to which a low power level is to beallocated. To these two signal points, transmission weights are giventhrough Precoding 0 and Precoding 1.

A specific example of new transmission weight selection is as follows.For example, in Transmission Mode 3 when the number of antenna ports istwo, as in Table 1, a transmission weight of Codebook Index=0 isselected based on a transmission weight selection rule of LTE, whereasin a new transmission weight selection rule, a transmission weight ofCodebook Index=1, for example, can also be selected as well as CodebookIndex=0.

As another example of new transmission weight selection, in TransmissionMode 4 when the number of antenna ports is two, Codebook Index=1 or 2 isselected, whereas 0, for example, can also be selected in a newtransmission weight selection rule as with the aforementioned example.

In selecting a transmission weight, the base station 100 may dynamicallydecide or statically define a transmission weight to be selected. In thecase of dynamically deciding the transmission weight, the base station100 should report which transmission weight has been selected to areceiver (the terminal device 200); accordingly, the base station 100reports an index of a selected transmission weight to a target receiverthrough RRC signaling, system information, downlink control information,or the like. This reporting is executed by the reporting unit 153. Thebase station 100 may report an index of a selected transmission weightevery time selection is performed, or may determine a timing when atransmission weight can be switched, and perform switching only at thetiming and report the index to the target receiver.

The base station 100 may switch a transmission weight at a randomtiming, or on the basis of communication quality feedback from thereceiver. Alternatively, the base station 100 may switch a transmissionweight at constant timings, for example, every frame, or at a timingwhen a decoding error (e.g., CRC error) occurs at the receiver side.Alternatively, the base station 100 may switch a transmission weight ata timing of retransmission, or at a timing when a change of apredetermined value or more occurs in a distance to the receiveraccording to position information on the receiver.

FIG. 14 is a flowchart illustrating an operation example of the basestation 100 (transmitter) and the terminal device 200 (receiver)according to an embodiment of the present disclosure. FIG. 14illustrates an operation example of the base station 100 and theterminal device 200 when the base station 100 switches a transmissionweight. Hereinafter, the operation example of the base station 100 andthe terminal device 200 according to an embodiment of the presentdisclosure will be described with reference to FIG. 14.

First, the base station 100 determines whether it is a timing forswitching a transmission weight (step S111). The determination in stepS111 is performed by the transmission processing unit 151. The basestation 100 determines whether it is a timing for switching atransmission weight based on whether it is the above-described timing,for example. Note that the base station 100 may skip the determinationin step S111 in the case of switching a transmission weight at a randomtiming.

When it is determined in step S111 that it is a timing for switching atransmission weight (step S111, Yes), the base station 100 then reportsto the receiver (the terminal device 200) that it is a timing when atransmission weight can be switched (step S112). The process of stepS112 is performed by the reporting unit 153.

The receiver (the terminal device 200) that has received the report fromthe base station 100 determines whether to issue a transmission weightswitching request (step S113). The process of step S113 is executed bythe reception processing unit 243.

Then, following the process of step S113, the receiver (the terminaldevice 200) determines whether to issue a transmission weight switchingrequest to the base station 100 (step S114). When having determined toissue a transmission weight switching request to the base station 100(step S114, Yes), the receiver reports the transmission weight switchingrequest to the base station 100 (step S115). The determination processin step S114 may be executed by the reception processing unit 243, forexample. The reporting process in step S115 may be executed by thereporting unit 245, for example. The receiver may decide to issue atransmission weight switching request based on the quality of a signaltransmitted from the base station 100, or at a timing when a decodingerror of a received signal occurs. The receiver may report thetransmission weight switching request as part of RRC signaling or aspart of uplink control information.

When the base station 100 determines in step S111 that it is not atiming for switching a transmission weight (step S111, No) or when,following the process of step S113, the terminal device 200 determinesnot to issue a transmission weight switching request to the base station100 (step S114, No), the base station 100 or the terminal device 200skips the subsequent processes.

On the other hand, in the case of statically defining the transmissionweight, the base station 100 may, for example, associate a codebookindex with a power layer. In such a case, there is no need for the basestation 100 to report information on a transmission weight to thereceiver. FIG. 15 is an explanatory diagram illustrating an example ofassociating a codebook index with a power layer.

In the case where two signals are to be multiplexed, the base station100 may uniquely decide a codebook index according to informationindicating a low power level. For example, in NOMA SPC, a receiver thatreceives a signal to which a low power level has been allocated willreceive a report on information indicating that a process such asinterference cancellation should be performed, through RRC signaling,system information, downlink control information, or the like. In thiscase, by deciding beforehand that a receiver that has received thereport uses a unique value (e.g., Codebook Index=1) other than a valueused in related art as a codebook index, it is possible to use differenttransmission weights without newly adding a process of reportinginformation on a transmission weight.

Furthermore, the base station 100 may select a transmission weight, fromamong a plurality of quasi-statically selected transmission weights,based on a transmission weight by which a signal point other than thetarget signal point is to be multiplied. For example, the base station100 may select a transmission weight to be applied to a signal with alow power level based on information on a transmission weight to beapplied to a signal with a high power level. For example, the basestation 100 makes a decision in such a way that if a codebook index of atransmission weight to be applied to a signal with a high power level is0, a codebook index of a transmission weight to be applied to a signalwith a low power level is 1.

FIG. 16 is an explanatory diagram illustrating an example of receptioncharacteristics for combinations of codebook indices when SPC is appliedto two UEs. In the example of FIG. 16, the two UEs are both in TM3 anduse SPC. In FIG. 16, Precoding Matrix Indicator (PMI) is shown as acodebook index. The horizontal axis of FIG. 16 indicates averagereceived SNR [dB] in a user to which a low power level has beenallocated, and the vertical axis indicates block error rate (BLER)characteristics.

In FIG. 16, PMI is shown as PMI(A,B). “A” denotes a codebook index to beapplied to a signal with a low power level, and “B” denotes a codebookindex to be applied to a signal with a high power level.

As shown in FIG. 16, some combinations of codebook indices in SPC leadto poor error rate characteristics. That is, applying the switching ofthe transmission weight selection rule of the present embodiment in SPCserves as a remedy for poor error rate characteristics.

2. Application Examples Regarding Base Stations First ApplicationExample

FIG. 17 is a block diagram illustrating a first example of a schematicconfiguration of an eNB to which the technology of the presentdisclosure may be applied. An eNB 800 includes one or more antennas 810and a base station device 820. Each antenna 810 and the base stationdevice 820 may be connected to each other via an RF cable.

Each of the antennas 810 includes a single or multiple antenna elements(such as multiple antenna elements included in an MIMO antenna), and isused for the base station device 820 to transmit and receive radiosignals. The eNB 800 may include the multiple antennas 810, asillustrated in FIG. 17. For example, the multiple antennas 810 may becompatible with multiple frequency bands used by the eNB 800. AlthoughFIG. 17 illustrates the example in which the eNB 800 includes themultiple antennas 810, the eNB 800 may also include a single antenna810.

The base station device 820 includes a controller 821, a memory 822, anetwork interface 823, and a radio communication interface 825.

The controller 821 may be, for example, a CPU or a DSP, and operatesvarious functions of a higher layer of the base station device 820. Forexample, the controller 821 generates a data packet from data in signalsprocessed by the radio communication interface 825, and transfers thegenerated packet via the network interface 823. The controller 821 maybundle data from multiple base band processors to generate the bundledpacket, and transfer the generated bundled packet. The controller 821may have logical functions of performing control such as radio resourcecontrol, radio bearer control, mobility management, admission control,and scheduling. The control may be performed in corporation with an eNBor a core network node in the vicinity. The memory 822 includes RAM andROM, and stores a program that is executed by the controller 821, andvarious types of control data (such as a terminal list, transmissionpower data, and scheduling data).

The network interface 823 is a communication interface for connectingthe base station device 820 to a core network 824. The controller 821may communicate with a core network node or another eNB via the networkinterface 823. In that case, the eNB 800, and the core network node orthe other eNB may be connected to each other through a logical interface(such as an S1 interface and an X2 interface). The network interface 823may also be a wired communication interface or a radio communicationinterface for radio backhaul. If the network interface 823 is a radiocommunication interface, the network interface 823 may use a higherfrequency band for radio communication than a frequency band used by theradio communication interface 825.

The radio communication interface 825 supports any cellularcommunication scheme such as Long Term Evolution (LTE) and LTE-Advanced,and provides radio connection to a terminal positioned in a cell of theeNB 800 via the antenna 810. The radio communication interface 825 maytypically include, for example, a baseband (BB) processor 826 and an RFcircuit 827. The BB processor 826 may perform, for example,encoding/decoding, modulating/demodulating, andmultiplexing/demultiplexing, and performs various types of signalprocessing of layers (such as L1, medium access control (MAC), radiolink control (RLC), and a packet data convergence protocol (PDCP)). TheBB processor 826 may have a part or all of the above-described logicalfunctions instead of the controller 821. The BB processor 826 may be amemory that stores a communication control program, or a module thatincludes a processor and a related circuit configured to execute theprogram. Updating the program may allow the functions of the BBprocessor 826 to be changed. The module may be a card or a blade that isinserted into a slot of the base station device 820. Alternatively, themodule may also be a chip that is mounted on the card or the blade.Meanwhile, the RF circuit 827 may include, for example, a mixer, afilter, and an amplifier, and transmits and receives radio signals viathe antenna 810.

The radio communication interface 825 may include the multiple BBprocessors 826, as illustrated in FIG. 17. For example, the multiple BBprocessors 826 may be compatible with multiple frequency bands used bythe eNB 800. The radio communication interface 825 may include themultiple RF circuits 827, as illustrated in FIG. 17. For example, themultiple RF circuits 827 may be compatible with multiple antennaelements. Although FIG. 17 illustrates the example in which the radiocommunication interface 825 includes the multiple BB processors 826 andthe multiple RF circuits 827, the radio communication interface 825 mayalso include a single BB processor 826 or a single RF circuit 827.

In the eNB 800 shown in FIG. 17, one or more structural elementsincluded in the processing unit 150 (the transmission processing unit151 and/or the reporting unit 153) described with reference to FIG. 10may be implemented by the radio communication interface 825.Alternatively, at least some of these constituent elements may beimplemented by the controller 821. As an example, a module whichincludes a part (for example, the BB processor 826) or all of the radiocommunication interface 825 and/or the controller 821 may be mounted ineNB 800, and the one or more structural elements may be implemented bythe module. In this case, the module may store a program for causing theprocessor to function as the one or more structural elements (i.e., aprogram for causing the processor to execute operations of the one ormore structural elements) and may execute the program. As anotherexample, the program for causing the processor to function as the one ormore structural elements may be installed in the eNB 800, and the radiocommunication interface 825 (for example, the BB processor 826) and/orthe controller 821 may execute the program. As described above, the eNB800, the base station device 820, or the module may be provided as adevice which includes the one or more structural elements, and theprogram for causing the processor to function as the one or morestructural elements may be provided. In addition, a readable recordingmedium in which the program is recorded may be provided.

In addition, in the eNB 800 shown in FIG. 17, the radio communicationunit 120 described with reference to FIG. 10 may be implemented by theradio communication interface 825 (for example, the RF circuit 827).Moreover, the antenna unit 110 may be implemented by the antenna 810. Inaddition, the network communication unit 130 may be implemented by thecontroller 821 and/or the network interface 823. The storage unit 140may be implemented by the memory 822.

Second Application Example

FIG. 18 is a block diagram illustrating a second example of a schematicconfiguration of an eNB to which the technology of the presentdisclosure may be applied. An eNB 830 includes one or more antennas 840,a base station device 850, and an RRH 860. Each antenna 840 and the RRH860 may be connected to each other via an RF cable. The base stationdevice 850 and the RRH 860 may be connected to each other via a highspeed line such as an optical fiber cable.

Each of the antennas 840 includes a single or multiple antenna elements(such as multiple antenna elements included in an MIMO antenna), and isused for the RRH 860 to transmit and receive radio signals. The eNB 830may include the multiple antennas 840, as illustrated in FIG. 18. Forexample, the multiple antennas 840 may be compatible with multiplefrequency bands used by the eNB 830. Although FIG. 18 illustrates theexample in which the eNB 830 includes the multiple antennas 840, the eNB830 may also include a single antenna 840.

The base station device 850 includes a controller 851, a memory 852, anetwork interface 853, a radio communication interface 855, and aconnection interface 857. The controller 851, the memory 852, and thenetwork interface 853 are the same as the controller 821, the memory822, and the network interface 823 described with reference to FIG. 17.

The radio communication interface 855 supports any cellularcommunication scheme such as LTE and LTE-Advanced, and provides radiocommunication to a terminal positioned in a sector corresponding to theRRH 860 via the RRH 860 and the antenna 840. The radio communicationinterface 855 may typically include, for example, a BB processor 856.The BB processor 856 is the same as the BB processor 826 described withreference to FIG. 17, except the BB processor 856 is connected to the RFcircuit 864 of the RRH 860 via the connection interface 857. The radiocommunication interface 855 may include the multiple BB processors 856,as illustrated in FIG. 18. For example, the multiple BB processors 856may be compatible with multiple frequency bands used by the eNB 830.Although FIG. 18 illustrates the example in which the radiocommunication interface 855 includes the multiple BB processors 856, theradio communication interface 855 may also include a single BB processor856.

The connection interface 857 is an interface for connecting the basestation device 850 (radio communication interface 855) to the RRH 860.The connection interface 857 may also be a communication module forcommunication in the above-described high speed line that connects thebase station device 850 (radio communication interface 855) to the RRH860.

The RRH 860 includes a connection interface 861 and a radiocommunication interface 863.

The connection interface 861 is an interface for connecting the RRH 860(radio communication interface 863) to the base station device 850. Theconnection interface 861 may also be a communication module forcommunication in the above-described high speed line.

The radio communication interface 863 transmits and receives radiosignals via the antenna 840. The radio communication interface 863 maytypically include, for example, the RF circuit 864. The RF circuit 864may include, for example, a mixer, a filter, and an amplifier, andtransmits and receives radio signals via the antenna 840. The radiocommunication interface 863 may include multiple RF circuits 864, asillustrated in FIG. 18. For example, the multiple RF circuits 864 maysupport multiple antenna elements. Although FIG. 18 illustrates theexample in which the radio communication interface 863 includes themultiple RF circuits 864, the radio communication interface 863 may alsoinclude a single RF circuit 864.

In the eNB 830 shown in FIG. 18, one or more structural elementsincluded in the processing unit 150 (the transmission processing unit151 and/or the reporting unit 153) described with reference to FIG. 10may be implemented by the radio communication interface 855 and/or theradio communication interface 863. Alternatively, at least some of theseconstituent elements may be implemented by the controller 851. As anexample, a module which includes a part (for example, the BB processor856) or all of the radio communication interface 855 and/or thecontroller 851 may be mounted in eNB 830, and the one or more structuralelements may be implemented by the module. In this case, the module maystore a program for causing the processor to function as the one or morestructural elements (i.e., a program for causing the processor toexecute operations of the one or more structural elements) and mayexecute the program. As another example, the program for causing theprocessor to function as the one or more structural elements may beinstalled in the eNB 830, and the radio communication interface 855 (forexample, the BB processor 856) and/or the controller 851 may execute theprogram. As described above, the eNB 830, the base station device 850,or the module may be provided as a device which includes the one or morestructural elements, and the program for causing the processor tofunction as the one or more structural elements may be provided. Inaddition, a readable recording medium in which the program is recordedmay be provided.

In addition, in the eNB 830 shown in FIG. 18, the radio communicationunit 120 described, for example, with reference to FIG. 10 may beimplemented by the radio communication interface 863 (for example, theRF circuit 864). Moreover, the antenna unit 110 may be implemented bythe antenna 840. In addition, the network communication unit 130 may beimplemented by the controller 851 and/or the network interface 853. Thestorage unit 140 may be implemented by the memory 852.

3. Application Examples Regarding Terminal Devices First ApplicationExample

FIG. 19 is a block diagram illustrating an example of a schematicconfiguration of a smartphone 900 to which the technology of the presentdisclosure may be applied. The smartphone 900 includes a processor 901,a memory 902, a storage 903, an external connection interface 904, acamera 906, a sensor 907, a microphone 908, an input device 909, adisplay device 910, a speaker 911, a radio communication interface 912,one or more antenna switches 915, one or more antennas 916, a bus 917, abattery 918, and an auxiliary controller 919.

The processor 901 may be, for example, a CPU or a system on a chip(SoC), and controls functions of an application layer and another layerof the smartphone 900. The memory 902 includes RAM and ROM, and stores aprogram that is executed by the processor 901, and data. The storage 903may include a storage medium such as a semiconductor memory and a harddisk. The external connection interface 904 is an interface forconnecting an external device such as a memory card and a universalserial bus (USB) device to the smartphone 900.

The camera 906 includes an image sensor such as a charge coupled device(CCD) and a complementary metal oxide semiconductor (CMOS), andgenerates a captured image. The sensor 907 may include a group ofsensors such as a measurement sensor, a gyro sensor, a geomagneticsensor, and an acceleration sensor. The microphone 908 converts soundsthat are input to the smartphone 900 to audio signals. The input device909 includes, for example, a touch sensor configured to detect touchonto a screen of the display device 910, a keypad, a keyboard, a button,or a switch, and receives an operation or an information input from auser. The display device 910 includes a screen such as a liquid crystaldisplay (LCD) and an organic light-emitting diode (OLED) display, anddisplays an output image of the smartphone 900. The speaker 911 convertsaudio signals that are output from the smartphone 900 to sounds.

The radio communication interface 912 supports any cellularcommunication scheme such as LTE and LTE-Advanced, and performs radiocommunication. The radio communication interface 912 may typicallyinclude, for example, a BB processor 913 and an RF circuit 914. The BBprocessor 913 may perform, for example, encoding/decoding,modulating/demodulating, and multiplexing/demultiplexing, and performsvarious types of signal processing for radio communication. Meanwhile,the RF circuit 914 may include, for example, a mixer, a filter, and anamplifier, and transmits and receives radio signals via the antenna 916.The radio communication interface 913 may also be a one chip module thathas the BB processor 913 and the RF circuit 914 integrated thereon. Theradio communication interface 912 may include the multiple BB processors913 and the multiple RF circuits 914, as illustrated in FIG. 19.Although FIG. 19 illustrates the example in which the radiocommunication interface 913 includes the multiple BB processors 913 andthe multiple RF circuits 914, the radio communication interface 912 mayalso include a single BB processor 913 or a single RF circuit 914.

Furthermore, in addition to a cellular communication scheme, the radiocommunication interface 912 may support another type of radiocommunication scheme such as a short-distance wireless communicationscheme, a near field communication scheme, and a radio local areanetwork (LAN) scheme. In that case, the radio communication interface912 may include the BB processor 913 and the RF circuit 914 for eachradio communication scheme.

Each of the antenna switches 915 switches connection destinations of theantennas 916 among multiple circuits (such as circuits for differentradio communication schemes) included in the radio communicationinterface 912.

Each of the antennas 916 includes a single or multiple antenna elements(such as multiple antenna elements included in an MIMO antenna), and isused for the radio communication interface 912 to transmit and receiveradio signals. The smartphone 900 may include the multiple antennas 916,as illustrated in FIG. 19. Although FIG. 19 illustrates the example inwhich the smartphone 900 includes the multiple antennas 916, thesmartphone 900 may also include a single antenna 916.

Furthermore, the smartphone 900 may include the antenna 916 for eachradio communication scheme. In that case, the antenna switches 915 maybe omitted from the configuration of the smartphone 900.

The bus 917 connects the processor 901, the memory 902, the storage 903,the external connection interface 904, the camera 906, the sensor 907,the microphone 908, the input device 909, the display device 910, thespeaker 911, the radio communication interface 912, and the auxiliarycontroller 919 to each other. The battery 918 supplies power to blocksof the smartphone 900 illustrated in FIG. 19 via feeder lines, which arepartially shown as dashed lines in the figure. The auxiliary controller919 operates a minimum necessary function of the smartphone 900, forexample, in a sleep mode.

In the smartphone 900 shown in FIG. 19, one or more structural elementsincluded in the processing unit 240 (the acquisition unit 241 and/or thereception processing unit 243) described with reference to FIG. 11 maybe implemented by the radio communication interface 912. Alternatively,at least some of these constituent elements may be implemented by theprocessor 901 or the auxiliary controller 919. As an example, a modulewhich includes a part (for example, the BB processor 913) or all of theradio communication interface 912, the processor 901 and/or theauxiliary controller 919 may be mounted in the smartphone 900, and theone or more structural elements may be implemented by the module. Inthis case, the module may store a program for causing the processor tofunction as the one or more structural elements (i.e., a program forcausing the processor to execute operations of the one or morestructural elements) and may execute the program. As another example,the program for causing the processor to function as the one or morestructural elements may be installed in the smartphone 900, and theradio communication interface 912 (for example, the BB processor 913),the processor 901 and/or the auxiliary controller 919 may execute theprogram. As described above, the smartphone 900 or the module may beprovided as a device which includes the one or more structural elements,and the program for causing the processor to function as the one or morestructural elements may be provided. In addition, a readable recordingmedium in which the program is recorded may be provided.

In addition, in the smartphone 900 shown in FIG. 19, the radiocommunication unit 220 described, for example, with reference to FIG. 11may be implemented by the radio communication interface 912 (forexample, the RF circuit 914). Moreover, the antenna unit 210 may beimplemented by the antenna 916. The storage unit 230 may be implementedby the memory 902.

Second Application Example

FIG. 20 is a block diagram illustrating an example of a schematicconfiguration of a car navigation device 920 to which the technology ofthe present disclosure may be applied. The car navigation device 920includes a processor 921, a memory 922, a global positioning system(GPS) module 924, a sensor 925, a data interface 926, a content player927, a storage medium interface 928, an input device 929, a displaydevice 930, a speaker 931, a radio communication interface 933, one ormore antenna switches 936, one or more antennas 937, and a battery 938.

The processor 921 may be, for example, a CPU or a SoC, and controls anavigation function and another function of the car navigation device920. The memory 922 includes RAM and ROM, and stores a program that isexecuted by the processor 921, and data.

The GPS module 924 uses GPS signals received from a GPS satellite tomeasure a position (such as latitude, longitude, and altitude) of thecar navigation device 920. The sensor 925 may include a group of sensorssuch as a gyro sensor, a geomagnetic sensor, and a barometric sensor.The data interface 926 is connected to, for example, an in-vehiclenetwork 941 via a terminal that is not shown, and acquires datagenerated by the vehicle, such as vehicle speed data.

The content player 927 reproduces content stored in a storage medium(such as a CD and a DVD) that is inserted into the storage mediuminterface 928. The input device 929 includes, for example, a touchsensor configured to detect touch onto a screen of the display device930, a button, or a switch, and receives an operation or an informationinput from a user. The display device 930 includes a screen such as aLCD or an OLED display, and displays an image of the navigation functionor content that is reproduced. The speaker 931 outputs sounds of thenavigation function or the content that is reproduced.

The radio communication interface 933 supports any cellularcommunication scheme such as LET and LTE-Advanced, and performs radiocommunication. The radio communication interface 933 may typicallyinclude, for example, a BB processor 934 and an RF circuit 935. The BBprocessor 934 may perform, for example, encoding/decoding,modulating/demodulating, and multiplexing/demultiplexing, and performsvarious types of signal processing for radio communication. Meanwhile,the RF circuit 935 may include, for example, a mixer, a filter, and anamplifier, and transmits and receives radio signals via the antenna 937.The radio communication interface 933 may be a one chip module havingthe BB processor 934 and the RF circuit 935 integrated thereon. Theradio communication interface 933 may include the multiple BB processors934 and the multiple RF circuits 935, as illustrated in FIG. 20.Although FIG. 20 illustrates the example in which the radiocommunication interface 933 includes the multiple BB processors 934 andthe multiple RF circuits 935, the radio communication interface 933 mayalso include a single BB processor 934 or a single RF circuit 935.

Furthermore, in addition to a cellular communication scheme, the radiocommunication interface 933 may support another type of radiocommunication scheme such as a short-distance wireless communicationscheme, a near field communication scheme, and a radio LAN scheme. Inthat case, the radio communication interface 933 may include the BBprocessor 934 and the RF circuit 935 for each radio communicationscheme.

Each of the antenna switches 936 switches connection destinations of theantennas 937 among multiple circuits (such as circuits for differentradio communication schemes) included in the radio communicationinterface 933.

Each of the antennas 937 includes a single or multiple antenna elements(such as multiple antenna elements included in an MIMO antenna), and isused for the radio communication interface 933 to transmit and receiveradio signals. The car navigation device 920 may include the multipleantennas 937, as illustrated in FIG. 20. Although FIG. 20 illustratesthe example in which the car navigation device 920 includes the multipleantennas 937, the car navigation device 920 may also include a singleantenna 937.

Furthermore, the car navigation device 920 may include the antenna 937for each radio communication scheme. In that case, the antenna switches936 may be omitted from the configuration of the car navigation device920.

The battery 938 supplies power to blocks of the car navigation device920 illustrated in FIG. 20 via feeder lines that are partially shown asdashed lines in the figure. The battery 938 accumulates power suppliedform the vehicle.

In the car navigation device 920 shown in FIG. 20, one or morestructural elements included in the processing unit 240 (the acquisitionunit 241 and/or the reception processing unit 243) described withreference to FIG. 11 may be implemented by the radio communicationinterface 933. Alternatively, at least some of these constituentelements may be implemented by the processor 921. As an example, amodule which includes a part (for example, the BB processor 934) or allof the radio communication interface 933 and/or the controller 921 maybe mounted in the car navigation device 920, and the one or morestructural elements may be implemented by the module. In this case, themodule may store a program for causing the processor to function as theone or more structural elements (i.e., a program for causing theprocessor to execute operations of the one or more structural elements)and may execute the program. As another example, the program for causingthe processor to function as the one or more structural elements may beinstalled in the car navigation device 920, and the radio communicationinterface 933 (for example, the BB processor 934) and/or the controller921 may execute the program. As described above, the car navigationdevice 920 or the module may be provided as a device which includes theone or more structural elements, and the program for causing theprocessor to function as the one or more structural elements may beprovided. In addition, a readable recording medium in which the programis recorded may be provided.

In addition, in the car navigation device 920 shown in FIG. 20, theradio communication unit 220 described, for example, with reference toFIG. 11 may be implemented by the radio communication interface 933 (forexample, the RF circuit 935). Moreover, the antenna unit 210 may beimplemented by the antenna 937. The storage unit 230 may be implementedby the memory 922.

The technology of the present disclosure may also be realized as anin-vehicle system (or a vehicle) 940 including one or more blocks of thecar navigation device 920, the in-vehicle network 941, and a vehiclemodule 942. In other words, the in-vehicle system (or a vehicle) 940 maybe provided as a device which includes the acquisition unit 241 and/orthe reception processing unit 243. The vehicle module 942 generatesvehicle data such as vehicle speed, engine speed, and troubleinformation, and outputs the generated data to the in-vehicle network941.

4. Conclusion

The base station 100 according to an embodiment of the presentdisclosure selects a transmission weight by which signals to beSPC-multiplexed are to be multiplied. In selecting the transmissionweight, the base station 100 may either dynamically decide or staticallydefine the transmission weight to be selected.

The terminal device 200 according to an embodiment of the presentdisclosure receives a report on a transmission weight switchable timingfrom the base station 100, and reports a transmission weight switchingrequest to the base station 100 in response.

An embodiment of the present disclosure provides the base station 100and the terminal device 200 that can change a transmission weight bywhich a signal is to be multiplied for each of users for whichmultiplexing is performed, and can improve a bit error rate or implementa remedy for a poor bit error rate.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

Further, the effects described in this specification are merelyillustrative or exemplified effects, and are not limitative. That is,with or in the place of the above effects, the technology according tothe present disclosure may achieve other effects that are clear to thoseskilled in the art based on the description of this specification.

Additionally, the present technology may also be configured as below.

(1)A transmission device including:a transmission processing unit configured to select a transmissionweight by which a plurality of signal points are to be multiplied,multiply a signal of each signal point by the selected transmissionweight, and multiplex the multiplied plurality of signal points on asame frequency and time resource, wherein the transmission processingunit changes a selection rule of the transmission weight by which eachsignal point is to be multiplied.(2)The transmission device according to (1),wherein, in multiplexing the plurality of signal points multiplied bythe transmission weight on the same frequency and time resource, thetransmission processing unit changes a power level to be allocated toeach signal point.(3)The transmission device according to (2),wherein, in selecting the transmission weight, the transmissionprocessing unit switches a selection rule of the transmission weight bywhich the signal point with a low power level is to be multiplied.(4)The transmission device according to (3),wherein the transmission processing unit quasi-statically selects thetransmission weight.(5)The transmission device according to (4),wherein the transmission processing unit dynamically selects thetransmission weight from among a plurality of quasi-statically selectedtransmission weights.(6)The transmission device according to (5),wherein the transmission processing unit determines whether to switchthe transmission weight in dynamically selecting the transmissionweight.(7)The transmission device according to (6),wherein the transmission processing unit switches the transmissionweight at a random timing.(8)The transmission device according to (6),wherein the transmission processing unit switches the transmissionweight based on feedback from a reception device that receives atransmitted signal.(9)The transmission device according to (6),wherein the transmission processing unit switches the transmissionweight at a timing decided in advance.(10)The transmission device according to (6),wherein the transmission processing unit switches the transmissionweight at a timing when a decoding error occurs in a reception devicethat receives a transmitted signal.(11)The transmission device according to (6),wherein the transmission processing unit switches the transmissionweight at a timing of retransmission of a once transmitted signal.(12)The transmission device according to (6),wherein the transmission processing unit switches the transmissionweight based on position information on a reception device that receivesa transmitted signal.(13)The transmission device according to (5), further including:a reporting unit configured to report information on the transmissionweight switched by the transmission processing unit to a receptiondevice that receives a signal to be transmitted.(14)The transmission device according to (13),wherein the reporting unit reports the information on the transmissionweight as part of RRC signaling.(15)The transmission device according to (13),wherein the reporting unit reports the information on the transmissionweight as part of system information.(16)The transmission device according to (13),wherein the reporting unit reports the information on the transmissionweight as part of downlink control information.(17)The transmission device according to (13),wherein the reporting unit reports a codebook index of the transmissionweight as the information on the transmission weight.(18)The transmission device according to (13),wherein the reporting unit reports a switchable timing of thetransmission weight as the information on the transmission weight.(19)The transmission device according to (4),wherein the transmission processing unit selects the transmission weightbased on an index of a power layer, from among a plurality ofquasi-statically selected transmission weights.(20)The transmission device according to (4),wherein the transmission processing unit selects the transmission weightusing information on a process of cancelling interference, from among aplurality of quasi-statically selected transmission weights.(21)The transmission device according to (4),wherein the transmission processing unit selects the transmission weightbased on a transmission weight by which a signal point other than thetarget signal point is to be multiplied, from among a plurality ofquasi-statically selected transmission weights.(22)A reception device including:an acquisition unit configured to acquire a report transmitted from atransmission device that selects a transmission weight by which aplurality of signal points are to be multiplied, multiplies a signal ofeach signal point by the selected transmission weight, and multiplexesand transmits the multiplied plurality of signal points on a samefrequency and time resource, which report is on a switchable timing ofthe transmission weight; anda reporting unit configured to report a switching request of thetransmission weight to the transmission device when the acquisition unitacquires the report on the switchable timing of the transmission weight.(23)The reception device according to (22), further including:a reception processing unit configured to determine whether to reportthe switching request of the transmission weight when the acquisitionunit acquires the report on the switchable timing of the transmissionweight.(24)The reception device according to (23),wherein the reception processing unit determines whether to report theswitching request based on quality of a signal received from thetransmission device.(25)The reception device according to (23),wherein the reception processing unit causes the reporting unit toreport the switching request of the transmission weight at a timing whena decoding error of a signal received from the transmission deviceoccurs.(26)The reception device according to (22),wherein the reporting unit reports the switching request of thetransmission weight as part of RRC signaling.(27)The reception device according to (22),wherein the reporting unit reports the switching request of thetransmission weight as part of uplink control information.(28)A transmission method including:in selecting a transmission weight by which a plurality of signal pointsare to be multiplied, multiplying a signal of each signal point by theselected transmission weight, and multiplexing the multiplied pluralityof signal points on a same frequency and time resource, changing aselection rule of the transmission weight by which each signal point isto be multiplied.(29)A reception method including:acquiring a report transmitted from a transmission device that selects atransmission weight by which a plurality of signal points are to bemultiplied, multiplies a signal of each signal point by the selectedtransmission weight, and multiplexes and transmits the multipliedplurality of signal points on a same frequency and time resource, whichreport is on a switchable timing of the transmission weight; andreporting a switching request of the transmission weight to thetransmission device when the report on the switchable timing of thetransmission weight is acquired.(30)A computer program causing a computer to execute:in selecting a transmission weight by which a plurality of signal pointsare to be multiplied, multiplying a signal of each signal point by theselected transmission weight, and multiplexing the multiplied pluralityof signal points on a same frequency and time resource, changing aselection rule of the transmission weight by which each signal point isto be multiplied.(31)A computer program causing a computer to execute:acquiring a report transmitted from a transmission device that selects atransmission weight by which a plurality of signal points are to bemultiplied, multiplies a signal of each signal point by the selectedtransmission weight, and multiplexes and transmits the multipliedplurality of signal points on a same frequency and time resource, whichreport is on a switchable timing of the transmission weight; andreporting a switching request of the transmission weight to thetransmission device when the report on the switchable timing of thetransmission weight is acquired.(32)A device including:circuitry configured toselect a transmission weight by which each of a plurality of signalpoints is to be multiplied;multiply a signal corresponding to each of the plurality of signalpoints by the selected transmission weight;multiplex the multiplied signals corresponding to each of the pluralityof signal points on a same frequency and time resource; andmodify a selection rule corresponding to the transmission weight bywhich each of the plurality of signal points is to be multiplied.(33)The device of (32), whereinthe circuitry is configured to change a power level allocated to each ofthe plurality of signal points when multiplexing the multiplied signalscorresponding to each of the plurality of signal points on the samefrequency and time resource.(34)The device of (33), whereinthe circuitry is configured to select the transmission weight byswitching a selection rule of the transmission weight by which a signalpoint with a power level less than a predetermined value is to bemultiplied.(35)The device of (32), whereinthe circuitry is configured to quasi-statically select the transmissionweight.(36)The device of (32), whereinthe circuitry is configured to dynamically select the transmissionweight from among a plurality of quasi-statically selected transmissionweights.(37)The device of (36), whereinthe circuitry is configured to determine whether to switch thetransmission weight in dynamically selecting the transmission weight.(38)The device of (32), whereinthe circuitry is configured to switch the transmission weight at arandom timing.(39)The device of (32), whereinthe circuitry is configured to switch the transmission weight based onfeedback from a reception device that receives a transmitted signal.(40)The device of (32), whereinthe circuitry is configured to switch the transmission weight at apredetermined timing.(41)The device of (32), whereinthe circuitry is configured to switch the transmission weight inresponse to determining that a decoding error has occurred in areception device that receives a transmitted signal.(42)The device of (32), whereinthe circuitry is configured to switch the transmission weight at atiming of retransmission of a previously transmitted signal.(43)The device of (32), whereinthe circuitry is configured to switch the transmission weight based onposition information of a reception device that receives a transmittedsignal.(44)The device of (32), further including:a communication interface configured to report information on atransmission weight switched by the circuitry to a reception device thatreceives a signal to be transmitted.(45)The device of (44), whereinthe communication interface is configured to report the information onthe transmission weight as part of downlink control information.(46)The device of (44), whereinthe communication interface is configured to report a codebook index ofthe transmission weight as the information on the transmission weight.(47)The device of (44), whereinthe circuitry is configured to report a switchable timing of thetransmission weight as the information on the transmission weight.(48)The device of (35), whereinthe circuitry is configured to select the transmission weight based onan index of a power layer, from among a plurality of quasi-staticallyselected transmission weights.(49)The device of (35), whereinthe circuitry is configured to select the transmission weight usinginformation on a process of cancelling interference, from among aplurality of quasi-statically selected transmission weights.(50)The device of (35), whereinthe circuitry is configured to select the transmission weight for atarget signal point based on a transmission weight by which a signalpoint other than a target signal point is to be multiplied, from among aplurality of quasi-statically selected transmission weights.(51)A device including:circuitry configured to acquire a report transmitted from a transmissiondevice that selects a transmission weight by which each of a pluralityof signal points is to be multiplied, multiplies a signal correspondingto each signal point by the selected transmission weight, andmultiplexes and transmits the multiplied signals corresponding to eachof the plurality of signal points on a same frequency and time resource,wherein the report includes information indicating a switchable timingof the transmission weight; anda communication interface configured to report a switching request ofthe transmission weight to the transmission device upon acquiring thereport including information indicating the switchable timing of thetransmission weight.

REFERENCE SIGNS LIST

-   -   1 system    -   100 base station    -   101 cell    -   110 antenna unit    -   120 radio communication unit    -   130 network communication unit    -   140 storage unit    -   150 processing unit    -   151 transmission processing unit    -   153 reporting unit    -   200 terminal device    -   210 antenna unit    -   220 radio communication unit    -   230 storage unit    -   240 processing unit    -   241 acquisition unit    -   243 reception processing unit    -   245 reporting unit

1. A device comprising: circuitry configured to select a transmission weight by which each of a plurality of signal points is to be multiplied; multiply a signal corresponding to each of the plurality of signal points by the selected transmission weight; multiplex the multiplied signals corresponding to each of the plurality of signal points on a same frequency and time resource; and modify a selection rule corresponding to the transmission weight by which each of the plurality of signal points is to be multiplied.
 2. The device of claim 1, wherein the circuitry is configured to change a power level allocated to each of the plurality of signal points when multiplexing the multiplied signals corresponding to each of the plurality of signal points on the same frequency and time resource.
 3. The device of claim 2, wherein the circuitry is configured to select the transmission weight by switching a selection rule of the transmission weight by which a signal point with a power level less than a predetermined value is to be multiplied.
 4. The device of claim 1, wherein the circuitry is configured to quasi-statically select the transmission weight.
 5. The device of claim 1, wherein the circuitry is configured to dynamically select the transmission weight from among a plurality of quasi-statically selected transmission weights.
 6. The device of claim 5, wherein the circuitry is configured to determine whether to switch the transmission weight in dynamically selecting the transmission weight.
 7. The device of claim 1, wherein the circuitry is configured to switch the transmission weight at a random timing.
 8. The device of claim 1, wherein the circuitry is configured to switch the transmission weight based on feedback from a reception device that receives a transmitted signal.
 9. The device of claim 1, wherein the circuitry is configured to switch the transmission weight at a predetermined timing.
 10. The device of claim 1, wherein the circuitry is configured to switch the transmission weight in response to determining that a decoding error has occurred in a reception device that receives a transmitted signal.
 11. The device of claim 1, wherein the circuitry is configured to switch the transmission weight at a timing of retransmission of a previously transmitted signal.
 12. The device of claim 1, wherein the circuitry is configured to switch the transmission weight based on position information of a reception device that receives a transmitted signal.
 13. The device of claim 1, further comprising: a communication interface configured to report information on a transmission weight switched by the circuitry to a reception device that receives a signal to be transmitted.
 14. The device of claim 13, wherein the communication interface is configured to report the information on the transmission weight as part of downlink control information.
 15. The device of claim 13, wherein the communication interface is configured to report a codebook index of the transmission weight as the information on the transmission weight.
 16. The device of claim 13, wherein the circuitry is configured to report a switchable timing of the transmission weight as the information on the transmission weight.
 17. The device of claim 4, wherein the circuitry is configured to select the transmission weight based on an index of a power layer, from among a plurality of quasi-statically selected transmission weights.
 18. The device of claim 4, wherein the circuitry is configured to select the transmission weight using information on a process of cancelling interference, from among a plurality of quasi-statically selected transmission weights.
 19. The device of claim 4, wherein the circuitry is configured to select the transmission weight for a target signal point based on a transmission weight by which a signal point other than a target signal point is to be multiplied, from among a plurality of quasi-statically selected transmission weights.
 20. A device comprising: circuitry configured to acquire a report transmitted from a transmission device that selects a transmission weight by which each of a plurality of signal points is to be multiplied, multiplies a signal corresponding to each signal point by the selected transmission weight, and multiplexes and transmits the multiplied signals corresponding to each of the plurality of signal points on a same frequency and time resource, wherein the report includes information indicating a switchable timing of the transmission weight; and a communication interface configured to report a switching request of the transmission weight to the transmission device upon acquiring the report including information indicating the switchable timing of the transmission weight. 